[unreadable] The goal of this proposal is to develop a novel therapy for molecular inotropy, specifically, viral-mediated myocardial delivery of the calcium regulatory protein SERCA 2a (sarcoplasmic reticulum Ca 2[unreadable]ATPase) to large animals exhibiting heart failure in an attempt to restore function and improve survival without worsening energetic parameters. Congestive heart failure (CHF) represents an enormous clinical problem demanding effective therapeutic approaches. Despite advances in traditional approaches to its treatment, including pharmacologic management, myocardial revascularization, mechanical assist devices, and transplantation, CHF remains a leading cause of death worldwide. Therefore, a novel therapy aimed at decreasing the morbidity and mortality of CHF and improving the quality of life for millions of patients is particularly attractive. Cardiac gene therapy has shown promise in early animal studies and lends itself to the treatment of heart failure. A defect in intracellular calcium handling is known to be a key abnormality in both human and experimental CHF. Deficient Ca 2[unreadable]uptake by the sarcoplasmic reticulum (SR) during relaxation in failing hearts from humans and animal models has been associated with a decrease in the expression and activity of SR Ca2+ATPase (SERCA2a). Our preliminary work over the last five years have shown that 1) Gene transfer is an effective means of introducing the SERCA2a gene into myocytes in vitro and in vivo and 2) that increasing the expression of SERCA2a restores contractility and normalizes intracellular calcium cycling in a rodent model of CHF. We are now extending our experiments from rodents to porcine models. We aim to 1) determine the efficiency of transduction of viral vectors in cardiomyocytes isolated from pig hearts; 2) determine the efficiency of transduction of the AAV vectors and El-E4 deleted recombinant adenovirus following gene transfer in vivo in pigs; 3) test the proximal human brain natriuretic (hBNP) promoter (-408 to +100 relative to transcription start site) for the ability to be induced by pressure-overload versus ischemia. [unreadable] [unreadable]